title: Factor structure and normative data of the Sinhalese version of self reported Strength and Difficulties Questionnaire (SDQ) for adolescents.
abstract: OBJECTIVE
  To describe the normative data, factor structure and the internal consistency of the Sinhalese, self reported version of SDQ for adolescents.
  
  
  METHODS
  The present study was carried out in eight provinces in Sri Lanka. A sample of school going adolescents aged 12-16 years were selected from Sinhalese medium schools using a multi stage cluster sampling technique with probability proportionate to size. The component structure of the SDQ was examined using principal component analysis. Normative banding and the cut off values were determined, based on the distribution of raw data in this non-clinical sample.
  
  
  RESULTS
  The study sample consisted of 535 (45.3%) boys and 645 (54.5%) girls. Mean total difficulty score for girls (10.66±5.440) was significantly (p=0.014) higher than that for boys (9.93±4.671). Mean scores for emotional (2.97±2.009), conduct (2.11±1.755) and peer (2.24±1.760) subscales were also significantly higher among girls than that of boys (2.7±1.915, 1.78±1.406 and 2.04±1.383 respectively). In the factor analysis, only factor that was loaded with all five items in the original subscale was "emotional" and the loading values were more than .445 for all five items. None of the other extracted factors contained more than 3 items from one subscale. Internal consistency (Cronbach's alpha) for total difficulties was satisfactory in the total sample as well as in boys and girls separately (>.71). However, in all five subscales, Chrobach's alpha was less than six, showing a low homogeneity.
  
  
  CONCLUSIONS
  Factor structure and internal consistency of the current Sinhalese version of the self reported SDQ is not satisfactory. Revalidation of this version of SDQ is recommended to capture the intended objectives of the SDQ.
authors.affiliation: Department of Community Medicine, Faculty of Medicine and Allied Sciences, University of Rajarata, Sri Lanka.
authors.forename: S
authors.initials: S
authors.lastname: Perera
authors.forename: E
authors.initials: E
authors.lastname: Thalagala
authors.forename: S H
authors.initials: SH
authors.lastname: Chandrarathna
authors.forename: T C
authors.initials: TC
authors.lastname: Agampodi
authors.forename: D B
authors.initials: DB
authors.lastname: Nugegoda
authors.forename: S B
authors.initials: SB
authors.lastname: Agampodi
mesh_terms: D000293:Adolescent; D005163:Factor Analysis, Statistical; D006801:Humans; D025341:Principal Component Analysis; D011594:Psychometrics; D057566:Self Report; D013188:Sri Lanka; D011795:Surveys and Questionnaires